Category Archives: Wings

Time: 1 Hour

When I got home tonight I decided to get a little time in the hangar, they say you should do at least one thing even if small everyday, and decided to work on the tie-downs. First up was to tap the bottom hole to 3/8 – 16 threads. These holes will accept any tie-down either Van’s or a different brand. So I clamped the block in the vice and got out my tap kit.

I then cleaned out all the filings from the threads. Then I hit all the surfaces with a Scotch-Brite pad and cleaned with MEK. After drying I started the priming.

I will let these dry until tomorrow night and rivet the nut plates to the block and spacers. Van’s does it this way so that you can remove the tie-down bracket with just bolts and not having to drill out rivets.

Time:7 Hours

Today I started to rivet the fuel tank attach nut plates on the main spars. Each spar has 60 nut plates for the fuel tanks, 30 on the top and 30 on the bottom. Each wing has 12 nut plates that help hold the inspection panels on the bottom flange. Before starting to rivet I spot primed all the CS’s by using my Duplicolor primer sprayed on a paper plate and using Q-Tips to dap the primer in the holes. Then I set up my 3″ yoke in the pneumatic squeezer and set the depth for the AN426AD3-4 rivets and started squeezing away.

I then set up for the inspection panel plate nuts using the same rivets.

And the right spar is finished, on to the left.

Left spar done.

Now on to the 2 center section nut plates on each spar.

Working on the aircraft tie-down block is next in the plans. These blocks, 1 in each wing, will have a threaded hole in which you install a tie-down ring. This is what you will tie the airplane down when parking outside at an airport FBO. I first trimmed down the blocks to the correct length and labeled them left and right.

I then created the spacers that required for the tie-downs.

The plans have you drill one hole in the tie-down blocks and use a bolt to hold it in place. Then you can match drill the remaining 7 holes using the spar as the guide. The spacers need 1″ lightening holes in the center to reduce their weight. I used a Irwin Unibit in my drill press for this.

I then taped those spacers to the spar and clamped the tie-down block to the spar through the one hole already drilled. I also used a block of wood and a clamp to hold it securely. I checked that it was square with the spar before tightening it down.

I used the block to match drill the remaining holes, as I went I added a couple of bolts to help hold everything together.

I then took the parts over to the vise and drilled for the 4 nut plates that get riveted to the block.

I think they turned out pretty nice! I just need to tap the bottom hole to accept the tie-down ring. Then I will clean and prime so they can be bolted to the spars. I decided to call it a day, after 7 hours I was beat!

Time: 7 Hours

Today plan was to get all the countersinking done in the left and right spars. There are 72 nut plates in each side, 142 total. Each nut plate requires 3 countersinks, 2 for the flush rivet heads and 1 to accept the dimple of the overlying skin. So doing the math that’s 432 countersinks(CS) to drill! Well I will just eat this elephant one bite at a time and enjoy some college football at the same time.

Those photos show the all of the rivet CS’s done and the #8 screw holes done. Next up is the inspection plate cover screws which are a #6. I will use my #40 CS to do these holes but I will have to reset the depth as I was using it for the flush head rivets. Before I make that change I decided to go ahead one step and CS the the center section attach plate nuts. There are 2 on each wing and since I have the proper depth set this was a easy decision to complete this step now.

Once I finished the center section CS I moved on the the inspection plates. They are #6 screws so I reset the depth on the CS cage and started the process. It took me about 30 minutes to finish the 12 on one wing.

Tomorrow I will rivet the nut plates and work on the tie down brackets.

Time: 2 Hours

My good friend Glen Vokac stopped by to go over several steps in the wing building process. Mainly to help me set up my countersink cages that I will be using right off the start. I wanted some extra eyes and help with this step as it is work on the main wing spars. These are big and expensive so making a mistake here would be costly. We did a lot of talking and setting up of the tools. So the time has come to start making some progress! First task is to prep for the many nut plates that go on the spars. These nut plates will hold the fuel tank skin to the spar and the inspection plates on the bottom of the wing. Each nut plat will get two AN426 rivets to hold it to the spar. Those rivets need to be flush so the skin lays flat, so they need to be countersunk. First thing I did was run a strip of painters tape over the valley created by the pieces that make up the spar. This is so aluminum shavings don’t get caught there while drilling.

So I then started with my #40 reamer and brought all the holes up to final size then countersunk them. These are fairly easy as all I wanted to do was make them deep enough to have the head be flush. I just slowly increased the depth with the micro stop cage until I achieved that goal.

Next up are the center holes, the nut plates for the fuel tanks will be a #8 screw and the inspection plates will be a #6 screw. I started with the #8 holes and did about 10 of them before calling it a night. I’m taking my time with these! These holes become fairly large in this process. When they do the pilot will tend to move around as the hole gets bigger and cause “chattering”. This is not good and makes a bad looking countersink. To avoid this I’m using a piece of aluminum that Glen brought. It has three holes drilled into it. Two line up with the rivet holes and the middle is for the pilot of the countersink bit. This keeps the pilot centered as you drill and prevents the chattering.

I have read several blogs about the proper dimensions of the size of a #8 countersink. They all say that it should be between .365 and .375 inches. When I used my dimpled gauge sheet to judge the depth I ended up with .370 inch exactly in the middle! >

So this is what the #8 nut plates look like when all drilled, there are 60 in each spar for the top and bottom.

So now I have all weekend to work and the weather is supposed to be in the middle 70’s and sunny! It’s gonna be a great weekend now that I’m back in the Hangar!

Well today at 10:30am my wings arrived in grand style on a FedEx truck.

I found a little bit of damage to the larger crate on the bottom. Looks like something hit the box side and pushed it in a little as shown by the bottom plywood staples now being exposed.

Well I decided to un-crate the long one first and then ill hit the bigger one to see if there is any damage.

I have read about the mountain of packing paper that accompanies these crates, and this is just from the smaller crate.

I unpacked all the pieces and set in piles so that I could properly inventory them and place on my new shelves. When I got to the bottom I found three of the skins damaged from where the crate had pushed in. It was just enough to bend the skins and cause creases.

So a quick call to Anne at Van’s and a longer call to FedEx and the ball is rolling to get those parts replaced. Glad I don’t have to pay for the shipping as they are pretty big! Next up was to inventory all the parts and organize them. I have hooks above my garage door for the long pieces, a 20″ deep shelf long a beam for the skins and a set of six foot shelves that are 16″ deep for the ribs and spars.

I will leave the spars on the workbench for now cause they are things of beauty!

Tomorrow I will inventory the parts bags for all the nuts, bolts, rivets and other small parts to make sure everything is there. For now I just have a smile on my face to have another pile of aluminum to keep me busy this winter! 🙂